The articulated arm configuration for an awning that consists of an arm and forearm comprising respective tubular arms with ends terminating in plug-in parts that define articulation configurations is a classic design. The arm and forearm are joined together by means of an articulation formed by two of the said adjacent articulation configurations. Within the profile that makes up the body of the arm is the spring under traction that is joined at one end to a fixed point on the tubular profile and by the other end to a flexible tie bar, which is fixed at the other end to a core of the forearm articulation configuration. A portion of the mentioned flexible tie bar is supported on a surface of the said core relatively removed from the rotation axis of the articulation in order to create, in virtue of the tension produced by the spring under traction, a rotational torque that tends to maintain the arm and forearm in a open position.
International patent application WO 98/01638 of the actual applicant describes an articulation for supporting awnings of the type described above, which contributes a series of improvements for the articulation, and in which the mentioned flexible tie bar comprises a flat belt interiorly fitted with metal reinforcement filaments. This belt includes terminals at its two ends for joining the belt to the traction spring and the core respectively. The two ends of the belt include cast terminals for joining the belt to the elastic traction element and to the core. The said terminals are connected to the ends of the cited metal reinforcement filaments at the ends of the belts.
One inconvenience of this type of awning arm is that the increase in rotational torque provided by the lengthening of the elastic traction element as the arm and forearm move from an open position to a closed one turns out to be insufficient with respect to the increase in resisting torque generated by the tension in the awning at the end of the forearm, taking into account that the arm and forearm adopt ever-increasingly inclined positions with respect to the line of application of the tension in the awning as they close. When the awning canvas is completely wound onto the roll-up bar and the arm is fully folded, the elastic energy accumulated in the elastic traction element may be insufficient to push the loading bar towards an open position as the canvas is unwound.
There is, therefore, a need for an articulated awning arm with an improved elastic effect that provides an initial tension when the arm is sufficiently open to maintain the awning canvas with an adequate level of tension and that possesses sufficient accumulated elastic energy when the arm is closed to push the awning canvas to an open position as the canvas is unwound.